chown - Unix, Linux Command
chown - To change owner, change the user and/or group ownership of each given File to a new Owner. Chown can also change the ownership of a file to match the user/group of an existing reference file.
chown [Options]... NewOwner File... chown [Options]... :Group File... chown [Options]... --reference=RFILE File...
If used, NewOwner specifies the new owner and/or group as follows(with no embedded white space):
chown [OWNER] [ [:.] [GROUP] ]
Following are the examples of how the owner/group can be specified:
If only an OWNER (a user name or numeric user id) is given, that user is made the owner of each given file, and the files' group is not changed.
If the OWNER is followed by a colon or dot and a GROUP (a group name or numeric group id), with no spaces between them, the group ownership of the files is changed as well (to GROUP).
chown OWNER.GROUP chown OWNER:GROUP
If a colon or dot but no group name follows OWNER, that user is made the owner of the files and the group of the files is changed to OWNER's login group.
chown OWNER. chown OWNER:
If the colon or dot and following GROUP are given, but the owner is omitted, only the group of the files is changed; in this case, 'chown' performs the same function as 'chgrp'.
chown .GROUP chown :GROUP
|Verbosely describe the action for each File whose ownership actually changes.|
|--dereference||Do not act on symbolic links themselves but rather on what they point to.|
|Do not print error messages about files whose ownership cannot be changed.|
|Act on symbolic links themselves instead of what they point to. This is the default. This mode relies on the 'lchown' system call. On systems that do not provide the 'lchown' system call, 'chown' fails when a file specified on the command line is a symbolic link. By default, no diagnostic is issued for symbolic links encountered during a recursive traversal, but see '--verbose'.|
|--reference=FILE||Use the user and group of the reference FILE instead of an explicit NewOwner value.|
|Recursively change ownership of directories and their contents.|
|Verbosely describe the action (or non-action) taken for every FILE. If a symbolic link is encountered during a recursive traversal on a system without the 'lchown' system call, and '--no-dereference' is in effect, then issue a diagnostic saying neither the symbolic link nor its referent is being changed.|
Change the owner of file.
$ chown user1 sample.txt
Change the group of file.
$ chown :mygroup file.txt
Change both the owner and group of file in single command.
$ chown user1:mygroup file.txt